Project Summary Core B will conduct all the morphological and pathology analyses for Projects 1, 2, and 3. Papillary scoring is an essential part of the PPG, and Core B will analyze all surgical recordings from Projects 1 and 2 to quantify plaque and plug areas on all papillae and to ensure that papillary scoring across the projects is consistent. Human tissues will be collected by Project 2 from carefully categorized stone patients, and Core B will perform light and electron microscopy (LM and EM) using specialized stains on the biopsy material, and using micro- infrared spectroscopy (FT-IR) and Raman methods to identify mineral in the tissue. Core B will also prepare the frozen sections to be used by Project 3 for laser micro-dissection, along with immunostained sections to verify the biopsy content. All stones collected in Projects 1 and 2 will be analyzed by micro CT and conventional FT-IR to provide detailed information on stone type and percent mineral content. Core B will also perform atomic absorption spectrophotometric analysis of lithium to determine distal delivery of solutes in study patients (Project 1), and of calcium in tissue specimens (Project 3).